Conventionally, when a rope or wire is hooked on a ship, and the ship is pulled and towed, with respect to forward and backward input shafts in a device for decelerating and reversing ships, heavy load is acted in the radial direction of the shafts via an output gear coupled with a propeller and the like, due to the rope or the wire wound around the propeller. Accordingly, when a sliding bearing is used for the bearing of the input shaft, it is likely that excessive frictional heat is generated on a contact surface between the input shaft and the bearing, and seizure occurs.
Accordingly, there has been known a technology in which rolling bearings such as a ball bearing and a roller bearing are used to prevent the seizure, and the frictional heat generated is low (for example, see Patent Literature 1).
PTL 1: Japanese Unexamined Patent Application Publication No. 2006-112471